I usually print a 6x9 inch image area on a 8x10 or 8-1/2x11 piece of inkjet paper. At 300 dpi, that will require about a 14 MB RGB file size in Photoshop. Practically, I never resize to a discrete DPI/PPI but let the printer handle the downsample or upsample.

As suggested, if you shoot at the largest size and least compression in your best in the sense of higher megapixel camera, you can take your out of camera JPEG and then save it as a TIFF or PSD file. It likely will be close to the 14 MB file size.

That Northlight file is a good one to test print. Just Google inkjet test print and several other good ones will be available.

Some OEM web sites will post RAW files from their cameras. Sigma has in the past and if it is from an old enough camera or you have a recent enough version of Adobe Camera Raw, it will open the RAW file. These will be outstanding images for testing a printer.

1. Printers output is in DPI. Each printer has fixed choices for DPI, For example epsons have 360, 720, 1440 and 2880 DPI settings. More dots = higher quality image, but slower printing. It takes a matrix (2 dimensional array) of dots to represent 1 pixel.

2. Printers input is in PPI (pixels per inch). 300 PPI is considered photo quality. Newspaper print is closer to 72ppi...

3. The actual picture is in X by Y pixels in size. It can be printed at any ppi that you choose; this choice will in turn determine the size on the paper. There is a tag in the jpg files which specify ppi and in turn that will specify printed size, however these labels are optional and you do not have to print at the PPI listed in the file.

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1. D800 is the first camera with resolution so high that it simply does not matter.2. Most people who do not own/shoot d800 missunderstand it. Color depth and accuracy in addition to resolution is what makes d800 great. Resolution alone is over rated.

"1. Printers output is in DPI. Each printer has fixed choices for DPI, For example epsons have 360, 720, 1440 and 2880 DPI settings."

I let the printer extrapolate to its preferred DPI settings, if such a thing exists. That's just my practical impression/satisfaction/it's good enough for me after years of printing. But if what you say is so, wouldn't it be impossible to specify DPI before printing anyway, as the graphics program is designating pixels, not dots?????

"1. Printers output is in DPI. Each printer has fixed choices for DPI, For example epsons have 360, 720, 1440 and 2880 DPI settings."

I let the printer extrapolate to its preferred DPI settings, if such a thing exists. That's just my practical impression/satisfaction/it's good enough for me after years of printing. But if what you say is so, wouldn't it be impossible to specify DPI before printing anyway, as the graphics program is designating pixels, not dots?????

I think the questionable statement is "At 300 dpi, that will require about a 14 MB RGB file size in Photoshop."

That would be 300 ppi, it is an input resolution, not an output (on paper) resolution. It adds further to the confusion.

"1. Printers output is in DPI. Each printer has fixed choices for DPI, For example epsons have 360, 720, 1440 and 2880 DPI settings."

I let the printer extrapolate to its preferred DPI settings, if such a thing exists. That's just my practical impression/satisfaction/it's good enough for me after years of printing. But if what you say is so, wouldn't it be impossible to specify DPI before printing anyway, as the graphics program is designating pixels, not dots?????

1. Printer does no have "preferred" DPI. Printers have selectable choices of possible dpi. For Epsons it it 2880x1440, 1440x1440, 1440x720, 720x720 ... 360x360

2. Preferred PPI for printers are integer divisors of dpi choices; this way each pixel gets the same number of dots.

3. With modern printers the "preferred" PPI is not all that much better than it used to be, compared to non-preferred ppi. Modern printers use dithering, so a given pixel does not always translate to the same pattern of dots; pattern depends on neighboring pixels/dots. As the result input ppi being divisor of output dpi is not as important as it used to be; but it still helps.

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1. D800 is the first camera with resolution so high that it simply does not matter.2. Most people who do not own/shoot d800 missunderstand it. Color depth and accuracy in addition to resolution is what makes d800 great. Resolution alone is over rated.

Picture dimensions depend on the size of the image he wants to print. The resolution (PPI) should be around 300. The Megabyte size of the file should be as large as possible, to avoid loss of detail from jpg compression. Google image search is his best friend.

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1. D800 is the first camera with resolution so high that it simply does not matter.2. Most people who do not own/shoot d800 missunderstand it. Color depth and accuracy in addition to resolution is what makes d800 great. Resolution alone is over rated.